Arc rating is defined in Article 100, in part, as the value attributed to materials that describes their performance with exposure to an electrical arc discharge and is expressed in cal/cm². Informational Note No. 1 states, in part, that arc-rated clothing or equipment has been tested for exposure to an electric arc and that flame-resistant (FR) clothing without an arc rating has not been tested for exposure to an electric arc.

A) in joules
B) in decibels
C) in lumens
D) in calories